Georeferencing of collecting localities

J. Tomasz Giermakowski tomas at UNM.EDU
Fri Apr 11 14:33:10 CDT 2003

Fabio and others,

The best source of elevation for a given latitude/longitude that covers
the world is a digital elevation model (DEM) developed by USGS, known as
GTOPO30. It's resolution is approximately 1km but vertical accuracy
depends on the area of the world. Here's the link:

The caveat is that dealing with this imagery really requires someone with
a bit of GIS experience and moderately serious computing power (some of
the files can easily fill the RAM). The easiest way to assign elevation is
to do it AFTER the georeferencing is done.

For USA, most regions have 30m or 10m resolution DEM's also developed by
USGS. Depending on the application, it could really be an overkill (i'm
thinking of the previous post about "car-centric" collection localities).


tom giermakowski

> There are people here at the museum doing a lot of georeferencing, and
> they use a program called TOPO USA, made by DeLorme
> (, that has some of the
> features mentioned by Doug. However, I think it covers only the USA. I
> haven't used the program, but I have seen people using it, and it seems
> pretty helpful. When you load the elevation map, you get both the
> elevation and coordinates (lat - long) of the point where the mouse is.
> Today, by coincidence, we tried to do the same in ArcView 8.3, but we
> could not figure out how to read the elevation -- I don't know if it is
> possible in ArcView, maybe it is if you have the right data (i.e.,
> topographic layers).  What we had was probably a representation of the
> elevation, but not the precise (not sure how much) topographic values
> like TOPO USA has.
> I do not know if there are online resources available that will provide
> lat/long AND elevation for places outside of the US. If there are such
> resources, please tell us -- I am sure a lot of us could use them.
> Aloha,  Fabio
> Fabio Moretzsohn, Ph.D.
> Invertebrate Zoology, Bishop Museum
> 1525 Bernice Street
> Honolulu, Hawaii  96817 U.S.A.
> Ph: (808) 848-4103, Fax (808) 847-8252
> Email: fabio at

J. Tom Giermakowski
Division of Amphibians and Reptiles
Museum of Southwestern Biology          tel: 505.277.5130
MSC03 2020                              fax: 505.277.0304
University of New Mexico                email: tomas at
ALBUQUERQUE, NM 87131-0001, USA         web:

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